KEK Theory workshop 2019

Session

Invited talks

Dec 3, 2019, 10:30 AM

Kobayashi Hall, Kenkyu-Honkan bldg. 1F (KEK)

Conveners

Invited talks: Hikaru KAWAI

• Chair: Hiroshi Suzuki

Invited talks: Masatoshi YAMADA

• Chair: Hiroshi Suzuki

Invited talks: Nobuyoshi OHTA

• Chair: Hiroshi Suzuki

Invited talks: Hiroshi SUZUKI

• Chair: Yoshio Kikukawa

Invited talks: Gerald DUNNE

• Chair: Yoshio Kikukawa

Invited talks: Tatsuhiro MISUMI

• Chair: Yoshio Kikukawa

Invited talks: Masafumi FUKUMA

• Chair: Kazuya Yonekura

Invited talks: Jaroslav TRNKA

• Chair: Kazuya Yonekura

Invited talks: Song HE

• Chair: Asato Tsuchiya

Invited talks: Yoshimasa HIDAKA

• Chair: Asato Tsuchiya

Invited talks: Takahiro NISHINAKA

• Chair: Asato Tsuchiya

Invited talks: Masahito YAMAZAKI

• Chair: Takahiro Nishinaka

Invited talks: Kazuya YONEKURA

• Chair: Takahiro Nishinaka

Invited talks: Yoshihisa KITAZAWA

• Chair: Takahiro Nishinaka

5. Quantum Gravity and Naturalness

Prof. Hikaru Kawai

12/3/19, 10:30 AM

We discuss the possibility that naturalness can be understood as an effect of quantum gravity. In particular, we will consider a mechanism by which the electroweak scale is naturally obtained from the Planck scale.

6. Status of asymptotic safety in gravity-matter systems

Dr Masatoshi Yamada

12/3/19, 11:30 AM

Asymptotically safe quantum gravity is one of candidates for quantum gravity. It is essential that there exists a non-trivial fixed point for gravitational couplings. In this talk we review the current status of the asymptotic safety scenario for gravity-matter systems.

7. An Approach to Quantum Gravity -- Asymptotic Safety --

Prof. Nobuyoshi Ohta

12/3/19, 1:30 PM

We explain an approach to formulate quantum gravity within the framework of local quantum field theory using functional renormalization group. called asymptotic safety. Starting how the approach is formulated, we intoduce the notion of critical surface and discuss its dimensionality. Several physical aspects of this approach are also discussed including quantum effective action derived from...

8. IR renormalon in a compactified spacetime: the case of the QCD(adj.) on $R^3\times S^1$

Prof. Hiroshi Suzuki

12/4/19, 9:30 AM

An interesting possibility that the ambiguity in perturbation theory caused by the IR renormalon is cancelled by the instability associated with a semi-classical object called bion has been suggested in the context of the resurgence program of asymptotically-free quantum field theories. To reinforce this picture on the IR renormalon, the understanding of the IR renormalon in a compactified...

9. Resurgence and Phase Transitions

Prof. Gerald Dunne

12/4/19, 10:30 AM

Resurgent asymptotics unifies perturbative and non-perturbative methods in quantum mechanics and quantum field theory, and gives a new perspective on phase transitions. I present an introduction to the basic ideas behind resurgence and several physical examples of phase transitions that can be probed this way, including the finite N approach to large N phase transitions. I also discuss new...

16. Power of ZN-twisted boundary condition ~Resurgence and Continuity~

Prof. Tatsuhiro Misumi

12/4/19, 11:30 AM

Quantum field theories on the circle-compactified spacetime are quite worth investigating in terms of finite-T physics, resurgence theory and volume independence. In particular, several evidences indicate that the compactified theories with ZN-twisted boundary condition maintain the vacuum structure of the original uncompactified theory. We discuss this property, called adiabatic continuity,...

11. Sign problem and the tempered Lefschetz thimble method

Prof. Masafumi Fukuma

12/4/19, 1:30 PM

The tempered Lefschetz thimble method (TLTM) [arXiv:1703.00861] is a parallel-tempering algorithm towards solving the numerical sign problem. It uses the flow time of the antiholomorphic gradient flow as a tempering parameter and is expected to tame both the sign and multimodal problems simultaneously. In this talk, after reviewing the TLTM, we apply the method to various problems, including...

13. Deep into the Amplituhedron

Prof. Jaroslav Trnka

12/4/19, 2:30 PM

14. Scattering Amplitudes from Geometries at Infinity

Prof. Song He

12/5/19, 9:30 AM

12. QCD phase diagram and the possibility of topological phases

Prof. Yoshimasa Hidaka

12/5/19, 10:30 AM

I discuss possible phases of QCD at finite temperature, density and/or strong fields. In particular, I discuss the possibility of topological phases in dense QCD matter.

34. S-duality for gauged Argyres-Douglas theories

Prof. Takahiro Nishinaka

12/5/19, 11:30 AM

15. Swampland Phenomenology

Prof. Masahito Yamazaki

12/6/19, 9:30 AM

10. Anomaly matching in QCD thermal phase transition

Prof. Kazuya Yonekura

12/6/19, 10:30 AM

I will talk about a nonperturbative constraint on QCD thermal phase transition. First, I discuss a rigorous constraint from 't Hooft anomaly matching when the quarks are massless and we introduce an imaginary baryon chemical potential at the Roberge-Weiss point. Then, I discuss the reason why I think the constraint is also relevant for the QCD phase transition without any imaginary chemical...

17. Asymptotic Freedom in de Sitter Space

Prof. Yoshihisa Kitazawa

12/6/19, 11:30 AM

We investigate infrared dynamics of four-dimensional Einstein gravity in de Sitter space. With the accelerated expansion of the universe, conformal zero modes accumulate at the horizon. The inflaton reresent the characteristic scale of the zero mode distribution. Furthermore, the introduction of an inflaton in the low energy effective theory is necessary to preserve Lorentz symmetry. We...